Jiangxia Li

Lack of association between ADAM33 gene and asthma in a Chinese population.

Asthma is a complex polygenic disease with gene–environment interactions being important. It has been previously suggested that ADAM33, which is a member of a gene family that encodes membrane‐anchored proteins with a disintegrin and a metalloprotease domain, is primarily expressed in lung fibroblasts and bronchial smooth muscle cells and has been associated with airway remodelling and bronchial hyperresponsiveness. A significant association has previously been demonstrated between single nucleotide polymorphisms (SNPs) and haplotypes of the ADAM33 and asthma in ethnically diverse populations. To assess whether SNPs or haplotypes of ADAM33 are related to asthma in a Chinese Han population, we genotyped three SNPs of ADAM33 (7575G/A in intron 6, 11188A/T in intron 19, and 12433T/C in exon 20) in a case‐control study involving 296 patients with asthma and 270 healthy controls. No significant association was detected between these three SNPs and asthma susceptibility in the Chinese population.

miR-155 Deficiency Ameliorates Autoimmune Inflammation of Systemic Lupus Erythematosus by Targeting S1pr1 in Faslpr/lpr Mice

MicroRNA-155 (miR-155) was previously found involved in the development of systemic lupus erythematosus (SLE) and other autoimmune diseases and the inflammatory response; however, the detailed mechanism of miR-155 in SLE is not fully understood. To explore the in vivo role of miR-155 in the pathogenesis of SLE, miR-155–deficient Faslpr/lpr (miR-155−/−Faslpr/lpr) mice were obtained by crossing miR-155−/− and Faslpr/lpr mice. Clinical SLE features such as glomerulonephritis, autoantibody levels, and immune system cell populations were compared between miR-155−/−Faslpr/lpr and Faslpr/lpr mice. Microarray analysis, RT-PCR, Western blot, and luciferase reporter gene assay were used to identify the target gene of miR-155. miR-155−/−Faslpr/lpr mice showed milder SLE clinical features than did Faslpr/lprmice. As compared with Faslpr/lpr mice, miR-155−/−Faslpr/lpr mice showed less deposition of total IgA, IgM, and IgG and less infiltration of inflammatory cells in the kidney. Moreover, the serum levels of IL-4 and IL-17a, secreted by Th2 and Th17 cells, were lower in miR-155−/−Faslpr/lpr than Faslpr/lpr mice; the CD4+/CD8+ T cell ratio was restored in miR-155−/−Faslpr/lpr mice as well. Sphingosine-1-phosphate receptor 1 (S1PR1) was found as a new target gene of miR-155 by in vitro and in vivo studies; its expression was decreased in SLE patients and Faslpr/lpr mice. miR-155−/−Faslpr/lpr mice are resistant to the development of SLE by the regulation of the target gene S1pr1. miR-155 might be a new target for therapeutic intervention in SLE.

A novel mutation of keratin 9 in epidermolytic palmoplantar keratoderma combined with knuckle pads

Epidermolytic palmoplantar keratoderma (EPPK) is an autosomal dominantly inherited disease. We studied a family from Shandong, China, having patients suffering from EPPK with a unique symptom—knuckle pads. We noticed that both the hyperkeratosis and knuckle pads in the Chinese family were friction‐related. Candidate gene analysis was carried out using linkage analysis and direct sequencing. A novel L160F mutation in keratin 9 was found, and its effects on the secondary structure of keratin 9 were studied. We predict that the L160F mutation is also responsible for the knuckle pads in the family. Our study provides a new clue for the study of the function of keratin 9.

Absence of association between two insertion/deletion coding genetic polymorphisms of TIM-1 gene and asthma in Chinese Han population

TIM‐1, a member of T‐cell immunoglobulin domain and mucin domain (TIM) gene family, was implicated as an asthma susceptibility gene in previous studies. TIM‐1 was expressed on CD4+ T cells after activation and its expression was sustained preferentially in T‐helper type 2 (TH2) but not in TH1 cells, therefore TIM‐1 became a good candidate gene for atopic diseases. Recent studies indicated that two insertion/deletion (ins/del) coding genetic polymorphisms in exon 4 of TIM‐1 were associated with asthma susceptibility in some but not in all populations. In order to investigate the relationship between TIM‐1 genetic polymorphisms and asthma in Chinese Han population, we performed a case‐control study for two insertion/deletion polymorphisms in TIM‐1 exon 4 (5383_5397ins/del and 5509_5511delCAA) and a single nucleotide polymorphism (SNP) in intron 8 (IVS 8+9 G/A) between a healthy control group of 309 people and an asthma patient group of 352 people recruited from Chinese Han population. The polymorphisms were genotyped and the allele and genotype frequencies were analysed, but none of the three polymorphisms showed association with asthma susceptibility in single‐locus association analyses. Linkage disequilibrium (LD) analyses demonstrated that the two insertion/deletion polymorphisms were in strong LD but the haplotypes constructed from these two polymorphisms showed no significant association with asthma. In conclusion, our findings suggest that 5383_5397ins/del, 5509_5511delCAA and SNP IVS 8+9 G/A polymorphisms are not associated with asthma susceptibility in Chinese Han population.

ETS1 variants confer susceptibility to ankylosing spondylitis in Han Chinese

IntroductionETS1 is a negative regulator of the Th17 differentiation gene and plays a central role in the pathogenesis of autoimmune diseases. We aimed to investigate whether polymorphisms in ETS1 confer susceptibility to ankylosing spondylitis (AS) in Han Chinese.MethodsWe selected seven single nucleotide polymorphisms (SNPs) within ETS1 based on HapMap data and previous genome-wide association study. Genotyping involved the TaqMan method in 1,015 patients with AS and 1,132 healthy controls from Shandong Province, and 352 AS patients and 400 healthy controls from Ningxia, a northwest region in China. Gene expression was determined by real-time PCR.ResultsThe SNP rs1128334 was strongly associated with AS (odds ratio 1.204, 95% confidence interval 1.06-1.37; P = 0.005). This association was confiexrmed in the Ningxia population (P = 0.015). Carriers of the haplotype TAT for rs12574073, rs1128334 and rs4937333 were associated with increased risk of AS and haplotype CGC with reduced risk as compared to controls. In addition, ETS1 expression was lower in AS patients than controls. The risk allele A of rs1128334 and haplotype A-T of rs1128334 and rs4937333 were associated with decreased expression of ETS1.ConclusionsCommon variants in ETS1 may contribute to AS susceptibility in Han Chinese people.

ORMDL3 contributes to the risk of atherosclerosis in Chinese Han population and mediates oxidized low-density lipoprotein-induced autophagy in endothelial cells.

ORMDL sphingolipid biosynthesis regulator 3 (ORMDL3) is a universally confirmed susceptibility gene for asthma and has recently emerged as a crucial modulator in lipid metabolism, inflammation and endoplasmic reticulum (ER) stress-the mechanisms also closely involved in atherosclerosis (AS). Here we first presented the evidence of two single nucleotide polymorphisms regulating ORMDL3 expression (rs7216389 and rs9303277) significantly associated with AS risk and the evidence of increased ORMDL3 expression in AS cases compared to controls, in Chinese Han population. Following the detection of its statistical correlation with AS, we further explored the functional relevance of ORMDL3 and hypothesized a potential role mediating autophagy as autophagy is activated upon modified lipid, inflammation and ER stress. Our results demonstrated that in endothelial cells oxidized low-density lipoprotein (ox-LDL) up-regulated ORMDL3 expression and knockdown of ORMDL3 alleviated not only ox-LDL-induced but also basal autophagy. BECN1 is essential for autophagy initiation and silencing of ORMDL3 suppressed ox-LDL-induced as well as basal BECN1 expression. In addition, deletion of ORMDL3 resulted in greater sensitivity to ox-LDL-induced cell death. Taken together, ORMDL3 might represent a causal gene mediating autophagy in endothelial cells in the pathogenesis of AS.

A locus for nonspecific X-linked mental retardation mapped to a 22.3 cM region of Xp11.3-q22.3.

By using several microsatellite markers scattered along the X chromosome, we studied a Chinese family with nonspecific X‐linked mental retardation (MRX84) to search for a region including the MRX84 locus that was linked to the markers. Two‐point linkage analysis demonstrated linkage between the disorder and several markers located at Xq22.2, with maximum LOD score Zmax = 2.41 at recombination fraction θ = 0 for DXS1191 and DXS1230, respectively. Recombination events were observed with flanking markers DXS8080 and DXS456, located at Xp11.3 and Xq22.3, respectively, and a region of approximately 22.3 cM was defined. Accordingly, markers distal to Xp11.3 and Xq22.3 segregated independently of the disease. The localized region observed in this Chinese family overlaps with 29 other MRX loci previously reported in Xp11.3‐q22.3. These results should contribute to the identification of the disease gene for the MRX84 disorder.

ORMDL3 Facilitates the Survival of Splenic B Cells via an ATF6α–Endoplasmic Reticulum Stress–Beclin1 Autophagy Regulatory Pathway

The genetic association of orosomucoid-like 3 (ORMDL3) with an array of immunoinflammatory disorders has been recently unraveled in multiple ethnic groups, and functional exploration has received attention of the particular relevance of this gene in endoplasmic reticulum stress, lipid metabolism, and inflammatory response. In this study, we demonstrated the upregulation of ORMDL3 in both patients with systemic lupus erythematosus and lupus mice compared with controls. By establishing ORMDL3 knockout mice (Ormdl3−/−), we showed that silencing Ormdl3 in vivo significantly decreased the proportions of mature B lymphocytes and transitional 2B cells in spleen and B1a cells from abdominal cavity perfusion fluid, the secretion of IgG and IgM, and the expression of Baff. Additionally, knockdown of Ormdl3 augmented the apoptosis of total splenic cells and splenic CD19+ B cells but did not affect B cell proliferation and cell cycle. Subsequently, we in vitro and in vivo demonstrated that ORMDL3 potentially mediates the autophagy via the ATF 6–Beclin1 autophagy pathway, and it facilitates the survival of splenic B cells via promoting autophagy and suppressing apoptosis. Taken together, we uncovered a role of ORMDL3 in fine-tuning B cell development and survival, besides highlighting a potential mechanism by which ORMDL3 regulates autophagy via ATF6 pathway.

Whole-Genome Linkage Analysis with Whole-Exome Sequencing Identifies a Novel Frameshift Variant in NEFH in a Chinese Family with Charcot-Marie-Tooth 2: A Novel Variant in NEFH for Charcot-Marie-Tooth 2

Background: Charcot-Marie-Tooth disease (CMT) is the most common neurodegenerative disorder of the peripheral nervous system. More than 50 genes/loci were found associated with the disease. We found a family with autosomal-dominant CMT2. Objective: To reveal the pathogenic gene of the family and further investigate the function of the variant. Methods: DNA underwent whole-genome linkage analysis for all family members and whole-exome sequencing for 2 affected members. Neurofilament light polypeptide and wild-type or mutant neurofilament heavy polypeptide (NEFH) were co-transfected into SW13 (vim–) cells. The nefh-knockdown zebrafish model was produced by using morpholino antisense oligonucleotides. Results: We identified a novel insertion variant (c.3057insG) in NEFH in the family. The variant led to the loss of a stop codon and an extended 41 amino acids in the protein. Immunofluorescence results revealed that mutant NEFH disrupted the neurofilament network and induced aggregation of NEFH protein. Knockdown of nefh in zebrafish caused a slightly or severely curled tail. The motor ability of nefh-knockdown embryos was impaired or even absent, and the embryos showed developmental defects of axons in motor neurons. The abnormal phenotype and axonal developmental defects could be rescued by injection of human wild-type but not human mutant NEFH mRNA. Conclusions: We identified a novel stop loss variant in NEFH that is likely pathogenic for CMT2, and the results provide further evidence for the role of an aberrant assembly of neurofilament in CMT.

WDFY4 Is Involved in Symptoms of Systemic Lupus Erythematosus by Modulating B Cell Fate via Noncanonical Autophagy

Genome-wide association studies have recently illuminated that WDFY4 is genetically associated with systemic lupus erythematosus (SLE) susceptibility in various ethnic groups. Despite strong genetic evidence suggesting a role of WDFY4 in SLE pathogenesis, its functional relevance is largely unknown. In this study, we generated Wdfy4 B lymphocyte conditional knockout (Wdfy4-CKO) mice and found that loss of Wdfy4 led to a decrease in number of total B cells and several subpopulations of B cells in the periphery and a defect in the transition from the pro– to pre–B cell stage in bone marrow. Also, Wdfy4-CKO mice showed impaired Ab responses as compared with controls when challenged with Ag. SLE phenotypes were effectively alleviated in Wdfy4-CKO mice, with significantly diminished pristane-elicited production of autoantibodies and glomerulonephritis. Genetic silencing of WDFY4 in B cells increased lipidation of LC3 independent of p62 and Beclin1, which are essential proteins of canonical autophagy. Our in vivo and in vitro data suggest that WDFY4 facilitates noncanonical autophagic activity. Our findings provide a novel functional link underlying the mechanism of SLE in which WDFY4 influences B cell fate via noncanonical autophagy.